Hydrolysis of nitrile group

The reaction proceeds via die hydrolysis of nitrile groups to an amide. The amides may also be A-formyl amines, which react with acid groups whereby volatile formic acid is shipped10 ... 

Generally, enzymatic hydrolysis of nitriles to the corresponding acids can either proceed stepwise, which is the case for catalysis by the nitrile hydratase/amidase enzyme system, or in one step in the case of nitrilases. Both systems have been investigated for surface hydrolysis of PAN [10], Complete hydrolysis with either system was monitored by quantification of ammonia and/or polyacrylic acid formed as a consequence of hydrolysis of nitrile groups [70-72], As a result, considerable increases in colour levels (e.g. 156% for commercial nitrilase) were found upon dyeing [72],... 

Enzymatic hydrolysis of PAN was first shown by Tauber et al. who monitored the formation of ammonia during hydrolysis of nitrile groups [99, 100]. Considering the fact that only a low 1.1% of nitrile groups are displayed on the polymer... 

Casale and Porter (1975) reported that copolymer formation between NBR and PVC may occur via mechanochemical radical generation on each polymer followed by recombination. The proposed mechanism was based on earlier studies by Akutin (1968). Later, Manoj et al. (1993b) postulated another mechanism for the same system involving hydrolysis of nitrile groups to amide or carboxylic acid followed by displacement of allylic chloride on PVC by amide-NH2 or acid-OH. 

Lergotrile (33) (see above) was hydroxylated at various positions in mammal systems (C-13, C-12, hydrolysis of nitrile group) and demethylated at N-6 (Smith and Rozassa, 1982 Axelrod et al, 1956). To find a parallel for this reaction and to prepare some standards of the metabolites more than 30 microorganisms have been screened for their hydroxylation ability (Davis etal., 1979). Only N-6 demethylation activity has been found in Streptomyces platensis. 

Aldehydes, Ketones, ndAcids. As with many aromatic compouads, the oxidatioa of methyl groups is an attractive synthetic route to both aldehydes and carboxyUc acids ia the quiaoliaes. The hydrolysis of dibromomethyl groups has also beea used for aldehydes and the hydrolysis of nitriles for carboxyhc acids. Detailed reviews of the synthesis of these compounds have appeared (4). 

A second practical route to AT-unsubstituted amides is by the controlled hydrolysis of nitriles, which can often be made (in the 5-position) by primary synthesis or (elsewhere) by displacement of an ammonio grouping. Thus 4,6-dimethylpyrimidine-2-carbonitrile (798 R = CN) in warm aqueous ammonia gives the amide (798 R = CONH2) in good yield... 

Methods of synthesis for carboxylic acids include (1) oxidation of alkyl-benzenes, (2) oxidative cleavage of alkenes, (3) oxidation of primary alcohols or aldehydes, (4) hydrolysis of nitriles, and (5) reaction of Grignard reagents with CO2 (carboxylation). General reactions of carboxylic acids include (1) loss of the acidic proton, (2) nucleophilic acyl substitution at the carbonyl group, (3) substitution on the a carbon, and (4) reduction. 

Acid-catalysed hydrolysis. The acid-catalysed hydrolysis of nitriles resembles the acid-catalysed hydrolysis of an amide, with protonation of the nitrogen of the cyano group activating the nucleophilic attack by... 

Hydrolysis of nitriles.1 N itriles are converted to thioamides by reaction with I (2 equivalents) at 40° overnight. Under these conditions most other functional groups are stable. Kinetic studies indicate that the reaction with nitriles is a two-step process, the first of which is analogous to an enc reaction to give a. Thioamides arc particularly useful precursors to amines by the method of Borch (2, 430 431), reaction with triethyloxonium tetrafluoroborate followed by reduction withNaBHj..- ... 

Copper-catalysts promoted with i) other group VIA or VIIIA metals and ii) alcaline or alcaline earth elements (IA or IIA) are used for selective hydrogenation of various organic compounds (1). Moreover Cu(Co) Zn-Al catalysts were extensively studied for the synthesis of methanol and of light alcohols (2,3). More recently, due to the development of fine chemical processes, detailed studies of copper catalysts were carried out in order to show, like for noble metals, the effect of supports (SMSI), of promoters and of activation-on metal dispersion or reduction, on alloy formation... For example modified copper catalysts are known for their utilization in the dehydrogenation of esters (4-6), in the hydrolysis of nitriles (7), in the selective hydrogenation of nitriles (8), in the amination of alcohols (9)... 

Preparation 64 illustrates the importance of this reaction in the sugar group. Eor the hydrolysis of nitriles, see p. 239. 

The hydrolysis of nitriles, which are organic molecules containing a cyano group, leads to carboxylic acid formation. These hydrolysis reactions can take place in either acidic or basic solutions. 

The nitrile group is a versatile building block, in particular since it can be converted into acids or amides. It undergoes hydrolysis but requires relatively harsh reaction conditions. Nature provides two enzymatic pathways for the hydrolysis of nitriles. The nitrilases convert nitriles directly into acids, while the nitrile hy-dratases release amides. These amides can then be hydrolysed by amidases (see also above). Often nitrile hydratases are combined with amidases in one host and a nitrile hydratase plus amidase activity can therefore be mistaken as the activity of a nitrilase (Scheme 6.32). A large variety of different nitrilases and nitrile hydratases are available [100, 101] and both types of enzyme have been used in industry [34, 38, 94]. 

Pagni and Kabalka reported acid-catalyzed hydrolysis of nitrile selectively into amide on the surface of unactivated AI2O3. The AI2O3 surface is polar and contains a layer of OH groups, which could serve as the source of water in this reaction (Scheme 5.30). 

Carboxylic acids are produced by the hydrolysis of nitrile compounds. In the hydrolysis the —CN group is converted to the —COOH group. Nitriles can be prepared by substitution reactions of alkyl halides with KCN or NaCN. 

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